- Family: Broomrape Family – Orobanchaceae
(formerly Figwort Family – Scrophulariaceae)
- Growing form: Annual herb. Hemiparasite.
- Height: 20–40 cm (8–16 in.). Stem abundantly branched, soft-haired.
- Flower: Corolla zygomorphic, bright yellow, fused, tubular, bilabiate, 15–20 mm (0.6–0.8 in.) long. Corolla tube usually curved. Upper lip hooded, flat-sided; lower lip 3-lobed. Calyx fused, campanulate (bell-shaped), woolly, 4-lobed, lobes approx. 2.5 mm (0.1 in.) long, narrowly triangular, branching, straight. Stamens 4. Gynoecium composed of 2 fused carpels. Lower flower-pairs separate in axils of subtending bracts, upper a one-sided terminal spike.
- Leaves: Opposite, short-stalked. Blade lanceolate–ovate, upper leaves toothed–lobed at base. Uppermost subtending bracts usually purple, sometimes yellowish white.
- Fruit: Elliptic capsule.
- Habitat: Young forests, broad-leaved forests, hedgerows, sloping meadows. Also an ornamental.
- Flowering time: June–July.
Wood cow-wheat is easy to recognize: its yellow flowers and purple upper leaves bring to mind the colours of the Swedish flag, and in fact it is known in some Swedish-speaking Finnish coastal areas as svenska flaggan, ’Swedish flag’. The powerful contrast between the colours of its upper leaves and flowers is behind its other Swedish-language name, natt och dag, ‘night and day’.
Many of beautiful wood cow-wheat’s current stands began as garden transplants. In the wild it favours broad-leaf forests and sloping meadows. It grows on one hand in the east of the country around Savonlinna–Parikkala and on the other hand in the south-west on the Åland Islands and around the western side of the Gulf of Finland. In the latter habitat it can be found growing alongside crested cow-wheat (M. cristatum), which is rare, and field cow-wheat (M. arvense), which is rarer still. Both species have been classified as vulnerable and the latter is protected.